68Thunder427

The fumes from my car will choke a horse. This thing is running very rich and the fumes are terrible. Adjusted the AF screws and no change. Edelbrock 650 cfm carb

stumpshot

I've got the same problem on my 75, 350 w/ Edelbock 600 cfm. I've tried needle and jet combos to run leaner, weaker springs, stronger springs, the whole 9 yards. When I get the combo leaned out it takes the stink out but the car dogs on part throttle. You might try the stuff I've tried with better luck though. I'm considering a carb spacer to see if that takes some of the heat off the carb.
Hope you figure it out better than I was able to.
Roy

mrscott25

Recommend checking your fuel pressure. Edlebrock wants 4-5.5 psi. Tons of guys have complained the carb runs too rich with higher pressure. Most of our factory pumps are running 6-9 psi.

I put on a performer 1406 with no problems but I installed a pressure regulator to run at 5 psi. There is a lot of people complaining about it online so i decided to just do it during my install. I can't promise that will solve your problem, but seems to be a fairly common complaint and probably a good place to look.

wombvette

Always had trouble with the power valve needles sticking when they were Carters and not Edelbrocks.

stumpshot

I'm running 4 psi on the pump and have been as low as 3 psi but the stink remains at idle. Running down the road everything seems to be fine.

MelWff

If you turn the idle mixture screws all the way in does the engine stall?

wilcar

My carbed c4 with a 600 edel carb was running rich so I followed the edel manual and went 3 stages lean which is .095 primary and .068 x .042 rods. Did the trick for me. Follow your manual and see how lean you can get with just a rod change.

68Thunder427

That is how you start to set a carb and yes it stalls. I did the normal turn in until it stalls and back out 1 1/2 turns and I have 17 in/hg vacuum but it is still pig rich. Went out as far as 2 more turns and still no change. A 650 cfm is small on a 454 so the venture may be sucking in to much fuel. try to do what I can with what I have currently but to be happy I guess it si going to be $700 on a good 800 - 850 cfm.

68Thunder427

I will look into it some more but I got out of the 1000nth's business (aka aerospace) some time ago and really don't feel like messing with it.

dugsgms74

Keep in mind that sometimes it smells rich but is actually lean, lean misfire will put alot of hydrocarbons out the tailpipe. Might want to pull the carb and see how much transfer slot you have exposed under the throttle blades, may have to play around with ignition advance and vacuum advance source to get the idle speed you want with the proper throttle opening. Good Luck.

REELAV8R

How much initial timing are you running?
Using port or manifold vacuum for vac advance?
The fuel has to be lit early enough to be burned before the exhaust valve opens. At idle fuel burns slower due to lower pressures in combustion chamber.
Other option is modding the carb for more bypass air. but it sounds like with 17 in of vac ( mild cam ) you should not need to do that.

68Thunder427

Initial is 24 total of 36.
Ported vacuum on HEI distributor.

bluedawg

Awesome advice there.

resdoggie

Smells like a timing issue. Have you read how to adjust timing using manifold vacuum? I would try that first before looking at changing the carb.

bluedawg

Don't know what size cam you have but your timing should plenty. I don't know much about the edelbrock carb but wilcar advice sounds pretty solid.

REELAV8R

That is plenty of initial. but since you are running ported vacuum then you're not going to get any advance from the vacuum advance until you come off idle.
My timing with manifold vacuum is 36* at idle. It helps to clean up the exhaust quite a bit. Your carb tuning has to be pretty close as well of course.
If you got 24* initial and 36 total then you have altered your mechanical advance? Or is 12* all that HEI is capable of? Normally they are in the neiborhood of 20* of advance I have found. Although that is for SBC, I have not messed with a BBC.

If you want to give it a try, hook up your vacuum to a manifold source. You'll probably have to back down your initial when you do that to reduce the timing at idle a little but that will give your starter a bit of break too.
What is your all in timing with the vacuum attached? You might be pretty advanced at cruise with your current initial setting.

MelWff

Why are you turning the screw out, counterclockwise, that richens the mixture on most carbs you should be going in.

REELAV8R

That edelbrock carb is baisically a q-jet copy isn't it?

If so then make sure things like float level is set correctly.

Like Melwif says, in on those idle screws is leaner not out.

The q-jet idle circuit is run through the primary jets. So if Edel is the same then are the primary jets too rich? How do the plugs look after running down the road and not letting it idle? Tail pipe black and sooty or clean and brown? Look for clues that the carb may be running rich or lean as a whole.
Lars is the carb expert here maybe he can shed some light.

68Thunder427

The car idles better / smoother on ported vacuum but yes I have tried it both ways. The biggest problem is that I have not found anyone that tunes carburated set ups around me. They all only do FI.